The use of thermoplastic polymers for many industrial applications is gaining increased acceptance today because of their excellent physical properties. For example, polycarbonates, especially aromatic polycarbonates formed from dihydric phenols, exhibit excellent physical attributes such as tensile strength, impact strength, and thermal stability. However, most polymers are generally deficient in at least one of several properties which curtails their use in certain products. For example, the use of polycarbonates in some applications, e.g., automotive, is limited somewhat because of their poor resistance to various organic solvents and other chemicals. On the other hand, materials such as the polyamides do not generally exhibit the superior physical properties of polycarbonates, but do exhibit excellent chemical resistance. It is thus apparent that a blend of several thermoplastic materials might result in a product possessing the best of each of their individual physical properties.
A particularly promising set of physical properties might result from the combination of the polycarbonates and polyamides discussed above. Blends of polycarbonates and various polyamides have been prepared in the past. For example, Japanese Kokai No. 116541/50 discloses a blend containing 80-95% by weight polycarbonate and 5-20% by weight of nylon 12. Furthermore, Japanese Patent Publication 26936/76 discloses adhesive compositions containing 5-40% by weight of a polycarbonate and 60-95% of a polyamide. Moreover, thermoplastic blends containing a polycarbonate and a polyamide along with a conjugated diene rubber are disclosed in U.S. Pat. No. 4,317,891.
While the polycarbonate/polyamide blends of the prior art may be suitable for some end uses, they generally exhibit serious disadvantages. For example, when molded, they often become severely laminated. Such undesirable lamination is often accompanied by poor impact strength. Furthermore, amine end groups of the polyamide react with carbonate bonds and thereby degrade the polycarbonate portion of the blend, resulting in loss of tensile strength, heat resistance and other desirable characteristics. It is thus readily apparent that the inherent chemical incompatibility between polycarbonates and polyamides results in blends of such materials having properties which are unacceptable for many uses.
Commonly assigned U.S. Pat. No. 4,732,934 describes a method for functionalizing a hydroxy-terminated thermoplastic polycarbonate with a functionalizing agent such as carbonyl-containing diacids followed by reaction with an amine-terminated polyamide resin. The entire content of that application is incorporated by reference.
The advantages accruing from blending two dissimilar polymers, each with its particular advantages, is not restricted to thermoplastic polycarbonates and nylon, but rather applies equally well to other engineering thermoplastics such as the aromatic polycarbonates, polyarylates, poly(arylene oxide)s, and polyarylethersulfones.
The synthesis of 1:1 polyesters of dicyclopentadiene dicarboxylic acid with the bis-(p-hydroxyphenyl)ether and with 2,2-bis-(p-hydroxyphenyl)propane is described by Mirva et al. in Bulletin of The Chemical Society of Japan, Vol. 50, No. 10, pp 2682-2685 (1977).
It is an object of the present invention to provide an improved method for functionalizing a thermoplastic resin having a structure comprising one or more recurring carbonate, ester, ether, or sulfone groups chemically linking hydrocarbon diradicals at least some of which are aromatic diradicals.
It is another object of the present invention to provide a functionalized thermoplastic resin which is capable of chemical reaction with a polyamide.
It is a further object to provide a functionalized bisphenol-A polycarbonate resin that forms a compatible blend with a polyamide such as nylon-6.
These and other objects will become evident to one skilled in the art on reading this entire specification including the appended claims.